Network management system

ABSTRACT

There is provided a network management system using wireless network management devices each having a plurality of security policies. With the network management system, the wireless network management devices can be concurrently used in networks with a plurality of security levels, and security can be ensured without installing firewalls externally, so that labor for setting and operating a network for redundancy can be saved. The network management system includes: a first network NW 1  to which plant management devices  11  and  12  are connected; a second network NW 2  to which field devices  51  to  5   n  are connected; and wireless network management devices  61  and  62  each having a firewall function and connected to the first network NW 1  and the second network NW 2.

TECHNICAL FIELD

The present invention relates to a network management system. In particular, the present invention relates to security management for networks.

BACKGROUND ART

FIG. 3 is a block diagram showing an example of background-art networks constructed based on a wireless communication standard ISA100.11a for industrial automation. Plant management devices 11 and 12 are connected to a first network NW1. These plant management devices 11 and 12 constitute a first security area SA1.

The first network NW1 is connected to a second network NW2 through a firewall 21.

Wireless network management devices 31 and 32 are devices each having a system manager function and a gateway function in ISA100.11a so that each of the wireless network management devices 31 and 32 can manage a wireless network and exchange information with any device on the wireless network.

In addition, the wireless network management devices 31 and 32 are not only connected to the second network NW2 but also connected to a third network NW3.

A maintenance terminal 4 is also connected to the third network NW3. These wireless network management devices 31 and 32 and the maintenance terminal 4 constitute a third security area SA3.

The third network NW3 is connected to a fourth network NW4 through a firewall 22.

Field devices 51 to 5 n are connected to the fourth network NW4. These field devices 51 to 5 n constitute a fifth security area SA5.

Here, the firewalls 21 and 22 are provided in network boundaries respectively in order to satisfy different security policies of the first security area SA1, the third security area SA3 and the fifth security area SA5.

Incidentally, for example, each security policy corresponds to information including IP address information for permitting connection to a corresponding network. When an IP address permitted for connection is set for a communication port, connection from another IP address through the communication port is not permitted.

A security policy for using the plant management devices 11 and 12 in a redundant configuration is set in the first security area SA1.

A security policy for using the wireless network management devices 31 and 32 in a redundant configuration is set in the third security area SA3.

A security policy for parallel driving the plurality of field devices 51 to 5 n is set in the fifth security area SA5.

Patent Literature 1 discloses a technique about a control network management system in which a process control system in industrial automation is configured as a wireless control network system, so that falsification etc. by a malicious third party can be avoided and a process control wireless communication signal which is required to have a high real-time property with ensured priority and a signal which is not required to have such a high real-time property can be made to coexist on one and the same network.

CITATION LIST Patent Literature

Patent Literature 1: JP-A-2011-142441

SUMMARY OF INVENTION Technical Problem

When a wireless network management device is newly connected in the configuration of FIG. 3, network boundaries must be protected using a firewall, which results in the cost for installing the firewall.

In addition, since the maintenance terminal directly connected to the wireless network management devices and the security of the third security area SA3 for redundancy must be taken into consideration, security policy management becomes complicated.

In addition, not only installation of a firewall but also equipment such as a network switch for constituting a network for redundancy are required.

Further, depending on the configuration of each network, communication for controlling a redundancy configuration for the network may go through another network and affect it.

The present invention is directed toward the problems in the background art. An object of the invention is to use wireless network management devices each having a plurality of security policies so that the wireless network management devices can be concurrently used in networks with a plurality of security levels.

Another object is to use a wireless network management device having a built-in firewall function to thereby ensure security without externally installing a firewall and save labor for setting and operating a network for redundancy.

An objection of the present invention can be achieved with following configurations.

(1) A network management system comprising:

-   -   a first network to which a plant management device is connected;     -   a second network to which a field device is connected; and     -   network management devices each having a firewall function and         connected to the first network and the second network.

(2) The system according to the above item (1), wherein the network management devices are connected to each other through a private communication line so as to be made redundant.

(3) The system according to the above items (1) or (2), wherein each of the network management devices has a plurality of communication ports for connecting to a plurality of networks.

(4) The system according to the above item (3), wherein respective security policies are assigned to a corresponding one of the communication ports, and each of the communication ports connects to a corresponding one of the networks each having a different security area.

(5) The system according to any one of the above items (1) to (4), wherein the network management system is constructed based on a wireless communication standard ISA100.11a for industrial automation.

Advantageous Effects of Invention

With these configurations, network management devices can be used concurrently in networks with a plurality of security levels.

In addition, it is possible to ensure security without separately providing firewalls so that it is possible to save labor for setting and operating a network for redundancy.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing an embodiment of the invention;

FIG. 2 is a block diagram showing a specific example of a wireless network management device 61; and

FIG. 3 is a block diagram showing an example of background-art networks.

DESCRIPTION OF EMBODIMENTS

The invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the invention. In FIG. 1, parts in common with those in FIG. 3 are referred to by the same numerals correspondingly.

Plant management devices 11 and 12 are connected to a first network NW1. These plant management devices 11 and 12 constitute a first security area SA1.

Wireless network management devices 61 and 62 are connected to the first network NW1 and a second network NW2. The wireless network management devices 61 and 62 are connected to each other through a private connection line. A maintenance terminal 7 is directly connected to the wireless network management device 61 or 62. These wireless network management devices 61 and 62 and the maintenance terminal 7 constitute a sixth security area SA6.

Field devices 51 to 5 n are connected to the second network NW2.

Each of the wireless network management devices 61 and 62 has not only a system manager function and a gateway function in a wireless communication standard ISA100.11a for industrial automation but also a firewall function. Due to the firewall function provided in each of the wireless network management devices 61 and 62, the wireless network management devices 61, and 62 can be connected directly to the networks NW1 and NW2.

When security policies are assigned to respective ports of the wireless network management devices 61 and 62, the wireless network management device 61, 62 can be connected to a plurality of networks with different security policies.

In addition, a private connection line is used for communication between the wireless network management devices 61 and 62 so that a redundant configuration can be constructed.

FIG. 2 is a block diagram showing a specific example of the wireless network management device 61. In FIG. 2, a redundancy management device connection communication port 61 b is connected to a packet processor 61 a, and a firewall function unit 61 c is also connected to the packet processor 61 a.

A filtering rule setting database 61 d is connected to the firewall function unit 61 c. In addition, a maintenance terminal direct link communication port 61 e, an upper network connection communication port 61 f and a lower network connection communication port 61 g are also connected to the firewall function unit 61 c.

In the configuration of FIG. 2, the firewall function unit 61 c acquires a filtering rule from the filtering rule setting database 61 d and operates in accordance therewith. Here, the filtering rule means information such as a table of IP addresses which are permitted for communication through the respective communication ports.

The firewall function unit 61 c controls received packets based on the filtering rule acquired from the filtering rule setting database 61 d, and packets permitted for communication can be delivered to the packet processor 61 a.

Information is synchronized between the wireless network management devices 61 and 62 which are configured redundantly so that the database in one wireless network management device 61 is equivalent to the database in the other wireless network management device 62.

For example, the redundancy management device connection communication port 61 b for directly connecting one wireless network management device 62 to the other wireless network management device 61 is used for communication for synchronizing the databases. Thus, the communication for synchronizing the databases can be prevented from flowing out on the upper network NW1 and the lower network NW2.

According to such a configuration, each of the wireless network management devices 61 and 62 can be connected to the plurality of networks NW1 and NW2 having different security levels.

The wireless network management devices 61 and 62 can be installed in a security level boundary without separately using firewalls.

Since the wireless network management devices 61 and 62 are connected directly to each other through the private connection line, redundancy can be achieved easily without the necessity of constructing a network for a redundancy configuration.

Further, since communication required for operating the wireless network management devices 61 and 62 in the redundancy configuration is performed through the private connection line, the communication gives no influence to other networks. The private connection line in this case is not limited to a network cable. A private cable or a backplane of a printed wiring board may be used as the private connection line.

In addition, although the embodiment has been described in the case where the network management devices are wireless network management devices by way of example, the invention is not limited thereto. When the network management devices are wired network management devices, an equivalent effect can be also obtained.

As described above, according to the invention, the wireless network management devices each having a built-in firewall function are used. Thus, it is possible to achieve a network management system in which the wireless network management devices can be concurrently used in networks with a plurality of security levels, and security can be ensured without installing firewalls externally, so that labor for setting and operating a network for redundancy can be saved.

Incidentally, in the above description, explanation and illustration of the invention are simply to show a specific preferred embodiment. Accordingly, the invention is not limited to the embodiment but may further include lots of changes and modifications without departing from the nature of the invention.

The present application is based on Japanese patent application No. 2012-142224, filed on Jun. 25, 2012, the contents of which are incorporated herein by reference.

REFERENCE SIGNS LIST

11, 12 plant management device

51 to 5 n field device

61, 62 wireless network management device

61 a packet processor

61 b redundancy management device connection communication port

61 c firewall function unit

61 d filtering rule setting database

61 e maintenance terminal direct link communication port

61 f upper network connection communication port

61 g lower network connection communication port 

1. A network management system comprising: a first network to which a plant management device is connected; a second network to which a field device is connected; and network management devices each having a firewall function and connected to the first network and the second network.
 2. The system according to claim 1, wherein the network management devices are connected to each other through a private communication line so as to be made redundant.
 3. The system according to 2 claim 2, wherein each of the network management devices has a plurality of communication ports for connecting to a plurality of networks.
 4. The system according to claim 3, wherein respective security policies are assigned to a corresponding one of the communication ports, and each of the communication ports connects to a corresponding one of the networks each having a different security area.
 5. The system according to claim 4, wherein the network management system is constructed based on a wireless communication standard ISA100.11a for industrial automation. 